Thanks for all your help guys. I think you've hit the nail on the
head. Now it is time for me to do some more reading, and fix this
puppy.

J

I have not seen much description on the solid state amp except that it has
MRF455 transistors. Because these devices were a favorite in the manufacture
of CB amplifiers, I am suspicious that the only output filtering is a HPF
set to cutoff around 30MHz.
So, running this amp on the lower HF bands would allow a lot of harmonic
energy to appear at the output.

Dale W4OP